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The 60-Day Rule for Property CGT
Since 27 October 2021, anyone selling UK residential property that doesn't qualify for full Private Residence Relief must report the gain and pay an estimate of the CGT due within 60 days of completion — using HMRC's dedicated CGT on UK property online service, separately from a normal Self Assessment return. The clock starts on the completion date, not exchange of contracts.
| Scenario | 60-day rule applies? |
|---|---|
| Selling your only/main home (full PRR) | No — usually no CGT due |
| Second home or holiday home | Yes |
| Buy-to-let / rental property | Yes |
| Inherited property you didn't live in | Yes |
Missing the deadline triggers automatic late-filing penalties and interest, even if you eventually pay the correct amount via Self Assessment later.
How this calculator works — Formulas & Method
Source: gov.uk/capital-gains-tax/rates, gov.uk/report-and-pay-your-capital-gains-tax · Deterministic calculation — no AI, no arbitrary estimation
Constants used
| Constant | Value | Source |
|---|---|---|
| Annual exempt amount | £3,000 | gov.uk/capital-gains-tax/rates, 2026/27 |
| Basic rate band upper limit | £50,270 taxable income | gov.uk Income Tax rates 2026/27 |
| CGT basic / higher rate | 18% / 24% | gov.uk/capital-gains-tax/rates |
| Property reporting deadline | 60 days from completion | gov.uk/report-and-pay-your-capital-gains-tax (disposals on/after 27 Oct 2021) |
Formulas
taxable_gain = max(0, gain − £3,000)
— Rate band —
basic_band_remaining = max(0, £50,270 − other_taxable_income)
at_18pct = min(taxable_gain, basic_band_remaining)
at_24pct = taxable_gain − at_18pct
cgt = at_18pct × 18% + at_24pct × 24%
Deterministic calculation based on official 2026/27 bands. Doesn't account for Private Residence Relief apportionment on partial-letting scenarios; always confirm your own position with HMRC or a qualified adviser.
Get It Filed Correctly, Not Just Estimated
This calculator gives an estimate — actually reporting and paying it correctly is a separate step with its own deadline and paperwork.
- Sold a second home or buy-to-let: the 60-day HMRC property CGT return is separate from your normal Self Assessment — miss it and penalties and interest apply automatically, starting from the completion date.
- Multiple disposals in one tax year: ordering and timing disposals across the 5/6 April boundary can materially change what you owe.
- Inherited or gifted assets: your acquisition cost for CGT purposes isn't always what you think — get the base cost confirmed.
- Business Asset Disposal Relief: can cut your rate to 18% on qualifying gains, but eligibility rules are strict.
A fixed-fee online accountant can handle the return and your wider Self Assessment together.
Compare Online Accountants →Transparency & Methodology
Methodology & Sources
Figures are public HMRC rates. For your exact position, use gov.uk/capital-gains-tax.
Not Tax or Legal Advice
Information only. Consult the Chartered Institute of Taxation or an adviser via the FCA Register.
Open Source
Formulas are public. Inspect on GitHub.